A silencer is an important part of ventilation

Functional ventilation is a prerequisite for good indoor air, and it is important to take it into account in both new and renovation construction. However, there are several sound-producing components in ventilation systems, the most significant of which are fan sounds, throttling damper sounds, flow sounds, crosstalk sounds and sounds produced by terminal devices. The noise they produce moves along the ventilation ducts into the rooms. A good silencer is a small but very important part of a seamlessly functioning ventilation system.

With the NORDsilencer NTF silencer, the noise level was reduced by 15 percent

The good ventilation of the ETS NORD production building is ensured by a combined supply and exhaust air device (RVC), which simultaneously brings fresh outdoor air into the building and blows out exhaust air. The RVC is efficient, but a large airflow passes through the device, which makes it loud.

In the immediate vicinity of the production building, directly opposite, there is an office building, where ventilation takes place through replacement air valves installed in the windows. However, due to the noise caused by the ventilation of the ETS NORD production building, the office windows could not be kept open. The measured starting level of the sound power level was high enough (71db) to disturb those working in the office. The steady hum of the ventilation device produced headache symptoms and fatigue.

The noise level was effectively reduced by placing two NTF 630-1000 silencers in the ventilation air exhaust and air intake ducts. Thanks to the effectively damping products, the sound level was lowered by 15 percent, from the initial level of 71 dB to 60 dB. The noise level was dampened so much that it can no longer be accurately measured or even heard.

The NORDsilencer MSK silencer reduced the noise level by 30 percent

In Tartu, a loud ventilation machine placed in the lowest building of the educational institution complex disturbed its surroundings with a noise of 86 dB(A). The noise level of the ventilation machine was compared to the noise levels of city center traffic. The noise disturbed the studying, but also made it impossible to open the windows. In the quiet hours of the night, the sound reflected forward and spread towards nearby residential areas, also disturbing the night’s sleep of the residents.

ETS NORD found a solution to the problem by installing an 1800 mm long MSK silencer with six 150 mm silencer cassettes in the exit air duct. With an efficient silencer, noise levels were reduced by as much as 30 percent, 60 dB(A), which corresponds to the noise level of a medium-sized office.